An image forming apparatus adapted to print an image on paper by an electrophotographic system sometimes performs image stabilization by rendering a correction image on an image carrier such as an intermediate transfer belt in spacing between sheets of paper. A toner consumption image is an example of the correction image used to discard old toner. There is spacing between sheets of paper when printing is performed on a cut sheet, in which case a toner consuming strip is formed on a belt between sheets of paper as described in JP 2011-100035 A. However, there is no spacing between sheets of paper when printing is performed on continuous paper, in which case a technique of a related art cannot be employed. Accordingly, JP 2006-91538 A proposes a method of forming a toner consuming strip in a margin on both edges of a sheet of paper in its width direction. It is however possible that there is no margin on a sheet of paper depending on image data, in which case the toner consuming strip cannot be formed. Therefore, when printing is performed on continuous paper, the toner consuming strip can be formed after completing a job.
A method of cleaning a toner consuming strip formed on a belt includes transferring the strip to paper and cleaning the strip with a cleaning blade provided on the belt. Hereinafter, the method of transferring the strip to paper will be referred to as forming on paper, and the method of cleaning the strip with the cleaning blade will be referred to as forming on a belt.
Forming on a belt has an advantage of generating no paper waste but has a constraint that the cleaning blade is turned up by friction force exceeding an allowable range when toner is excessively supplied to the blade. Due to this constraint, the amount of toner formed at a time on the belt is limited when forming on a belt, whereby it takes time to form the consuming strip.
On the other hand, forming on paper has an advantage of completing formation of the consuming strip in a short time but paper waste is generated from formation of the consuming strip.